The present invention is related to goggles for swimmers or divers.
For a more complete understanding of the invention, it is convenient to state beforehand a brief explanation in connection with the background art in the general field of underwater vision.
It is well known that the main problem to be faced in underwater vision is related to the fact that a non planar lens, which in the air would not cause visible or remarkable distortions, underwater is instead constituting a dioptric surface when separating water from air. It is to be pointed out that, in the present description and in the following claims, the term "lens" is intended to designate precisely the transparent optical diaphragm which in use is separating the water environment from the air volume comprised between such diaphragm and the surface of the user's face surrounding his eyes. Since water and air have quite different indexes of refraction, a curvature or a prismatic configuration of the lens hugely affects the refraction problems.
The general state of the art related to masks and goggles for swimmers or divers is diagrammatically shown in FIGS. 9 through 15, which are top plan and partially sectioned views of different conventional solutions.
FIG. 9 depicts a first known arrangement, normally employed in the case of diver masks, according to which a planar lens is provided, which can be formed by a single or by two symmetrical pieces, mutually kept co-planar by a rigid frame structure. This is the most common arrangement, even due to technological reasons deriving from easy manufacturing of planar glass lenses. In use, vision is without defects, but the visual field is necessarily limited, i.e. is laterally null. Moreover, hydrodynamic encumbrance is relevant.
FIG. 10 shows a configuration including two distinct non co-planar lenses: in this case the hydrodynamic encumbrance is reduced, but vision is quite poor. Actually, a same object seen in the water by both eyes originates two different images, which makes the user feel queasy.
FIG. 11 shows another known arrangement with a planar front lens and two lateral angled planar lenses. In this case the visual field is extended frontally and even laterally, but the image is broken into three pieces owing to the presence of two "blind" intermediate fields, corresponding to the angles formed between the central lens and two lateral lenses. The visual effect is accordingly very annoying, even in consideration of the fact that water refraction further magnifies the above two blind fields. Even in this case the user is subjected to nausea and confusion due to fact that the watched object somehow disappears and reappears.
FIGS. 12 and 13 show two known arrangements according to which the lens is entirely or partially curved, but with an erroneous curvature or with a position of the lens too much spaced ahead of the face and thus of the user's eyes. With the solution according to FIG. 12, in which the lens is entirely curved with a constant curvature radius, the image is doubled in correspondance of the central area of the lens (same defect as in the case of FIG. 10), owing to a too small curvature radius in that area. With the solution according to FIG. 13, wherein only the lateral portions of the lens are curved while the central front portion is planar, vision through the lateral areas produces out of focus and deformed images.
The situation does not improve with solutions, similar to that depicted in FIG. 12 or in FIG. 13, in which however the lens profile is curved not only in the horizontal plane, but also in the vertical plane, for instance such as disclosed and illustrated in German patent application DE-A-4218349. As a matter of fact such a substantially spherical curvature generates additional important visual defects: firstly, the central substantially planar area of the lens--which would provide a vision practically deprived of defects--is indeed too reduced, since delimited, not only at the right and left sides but also above and below the line joining the two optical centers of the lens, by a wide toric area originating important optical imperfections. Secondly, hugely deformed and out-of-focus images come from the two upper and lower curved areas, which hit portions of the user's eyes which are perfectly capable of accurate vision (the lower portion is the one which is normally employed when reading, while the upper portion is often used for far vision), and thus perfectly suitable to detect even the slightest optical defect, which again involves annoyance and nausea for the user.
In this specific field of goggles for swimming or diving, the currently available known solutions substantially correspond to those depicted in FIG. 10, already disclosed in the above, and in FIGS. 14 and 15. In the case of FIG. 14 two separate lenses are provided, having respective planar front surfaces and respective planar or cylindrical lateral surfaces. This solution involved the same defects as the arrangement previously disclosed with reference to FIG. 11, with the further inconveniences consisting of image doubling at the central separation area between the two lenses, when watching close objects.
In the case of FIG. 15 two distinct and separate lenses are also provided, each having a front portion merging with a lateral curved portion. This arrangement corresponds to that disclosed and illustrated in British patent GB-1431954, according to which the two lenses are part of two respective eyepieces centrally connected by a flexible bridging strap, whereby their mutual positioning is not rigid. Moreover, according to the above prior document the lenses have a curvature not only in the horizontal plane, but also in the vertical plane, according to a crowned configuration such that the respective central areas placed in use in front of the user's eyes are remarkably advanced, i.e. quite spaced ahead of the eyes themselves. This arrangement involves the sum of vision defects and inconveniences previously disclosed with reference to the solutions shown in FIGS. 10 and 13.
In addition to the above inconveniences from the optical point of view, the goggles for swimmers or divers according to the prior art are further affected by the following additional problems.
As far as wearing on the user's face is concerned, while in the case of the masks the bearing area thereof has a continuous annular shape so as to include the user's nose and to rests above the user's upper lip, in the case of goggles having two distinct eyepieces, whereby the user's nose is not enclosed, bearing on the user's face takes place through respective annular contact members in correspondence of the eye orbits. In order to ensure watertightness of these annular contact members, the two eyepieces are made mutually orientable in connection both to center-to-center and inclination thereof, which produces as a consequence important visual defects.
In addition to the above, a remarkable lack of comfort and a certain physical annoyance are experienced by the user. On the other hand, the presently existing goggles are suitable neither for plunging nor for fast swimming: protrusion of the two eyepieces forwardly and laterally of the user's face actually make these goggles hugely dragging and also unstable, since impact thereof with the water has a tendency to displace them from the correct position relative to the user's face. Moreover since the lenses of the conventional goggles are normally made of glass having a thickness generally comprised between three and five millimeters, these known goggles are equally unsuitable to be employed either for fast swimming, or in stream or rough water or for plunging, owing to their massive structure and relatively remarkable weight. Brittleness of glass, even if tempered, renders these goggles dangerous for instance even upon start plunging in swimming competition.
In the known swimming goggles wherein positioning of the lenses relative to the theoretical one is extremely variable owing to the absence of a mutual rigid connection therebetween, additional visual defects are originated consisting of image doubling and deformation, with a consequent nausea effect for the user.
A further problem is related to adjustment of the goggles retainer strap behind the user's head. Differently from the case of modern diving mask, in which sophisticated automatic buckle systems (such as those disclosed in U.S. Pat. No. 4,607,398 and in Italian Utility Model IT-U-167555) enable adjustment of the retainer strap by a simple operation with the mask on, not even one example of swimming goggles exists which does not instead require complex operations, which can not be performed while the goggles are worn by the user. This is due to the fact that no goggles designer has ever conceived an automatic buckle which is sufficiently compact to be housed within the small goggles size.